The retina is a complex tissue both structurally and functionally, with several structurally distinct compartments which subserve the major functions of visual information processing and integration. The capacity of the retina to receive and transmit complex visual information from the environment to the central nervous system is presumably dependent on both the proper development and continued maintenance of the precise geometric interrelationships which form between the retinal cell bodies, neurites and synapses. The goal of the research is to achieve a mechanistic understanding on the cellular and molecular level of the role of intercellular recognition and adhesion in the development of retinal organization. Its immediate aims are the further detailed analysis by immunological and biochemical techniques of molecules which we have previously shown to be involved in retinal cell interactions such as cell adhesion or in retinal differentiation. These experiments are directed at analyzing the control of expression of these molecules during retinal development, subjecting these molecules to biochemical analysis to determine their structures, to carry out functional studies of these molecules and their interaction with each other and with retinal cells, to use antibodies against these molecules to perturb their function in vitro and in vivo in order to examine their role during retinal development, and to use the antibodies to screen cDNA expression libraries derived from embryonic retina in order to obtain clones for these retinal adhesion and differentiation molecules. Information regarding the basic cellular and molecular mechanisms which guide pattern formation within the retina is essential not only to an understanding of retinal development per se, but will enhance our ability to understand and ultimately manage certain developmental and degenerative defects of the retina. In addition, the adult retina and optic nerve are incapable of regenerating following injury, and a better understanding of basic developmental mechanisms may lead to an understanding of this deficit in adult tissue and perhaps a means of restoring some degree of growth potential to these tissues. Thus the proposed research is relevant to clinical problems while it consists of basic studies which are related to the development and structure of the retina, including its cellular organization and synaptic connectivity patterns.